WO2021192499A1

WO2021192499A1 - Cutting insert and blade-tip-replaceable cutting tool

Info

Publication number: WO2021192499A1
Application number: PCT/JP2021/000765
Authority: WO
Inventors: 智洋村田
Original assignee: 株式会社Moldino
Priority date: 2020-03-26
Filing date: 2021-01-13
Publication date: 2021-09-30
Also published as: JP7464877B2; JPWO2021192499A1; EP4129546A4; EP4129546A1

Abstract

In the present invention, a convex arc-shaped corner blade (3) centered at a corner blade center line is formed at a corner section of a polygonal surface (2) of a polygonal plate-like insert body (1), the polygonal surface (2) has a land section (7) formed so as to gradually protrude in the insert center line direction from the corner blade (3) toward the inner side of the polygonal surface (2), and the polygonal surface (2) has, at a location inside of the land section (7), a rake face section (8) formed so as to gradually recede in the insert center line direction toward the inner side of the polygonal surface (2). In a range of 40° angle that is along the corner blade (3) from a first corner blade end to a second corner blade end and that is centered at the corner blade center line, the inclination angle (θ1) of the land section (7) with respect to a reference surface (P) perpendicular to the insert center line is equal to or greater than the inclination angle (θ2) of the rake face section (8) with respect to the reference surface (P), in a cross section taken along the corner blade center line.

Description

Cutting inserts and cutting tools with replaceable cutting edges

In the present invention, mounting holes are formed on the front and back polygonal surfaces of the insert body formed in the shape of a polygonal plate so as to penetrate the insert body centering on the insert center line. At the edge of the polygonal surface, a corner blade forming a convex arc shape, a main cutting blade extending linearly in the tangential direction of the corner blade, and a sub cutting that recedes with respect to the extension line of the main cutting blade. A cutting insert with a blade and a replaceable cutting edge that is detachably attached to an insert mounting seat formed on the outer periphery of the tip of the tool body in which such a cutting insert is rotated in the tool rotation direction around the axis. It is about tools.
The present application claims priority based on Japanese Patent Application No. 2020-56758 filed in Japan on March 26, 2020, the contents of which are incorporated herein by reference.

As such a cutting insert, for example, in Patent Document 1, a front surface portion having a long side and a short side and forming a substantially quadrangular shape in a plan view, a back surface portion arranged to face the front surface portion, and the front surface thereof. A corner portion formed at each of the four corners of the portion and the back surface portion, and a side surface portion connecting the front surface portion and the back surface portion, which are two long side side surface portions and two short side direction side surface portions. A fixing screw insertion hole penetrating from the central portion of the front surface portion to the back surface portion, and an intersecting ridge line portion where the front surface portion and the back surface portion intersect the short side direction side surface portion and the long side direction side surface portion. A cutting insert with a cutting edge portion having a cutting edge is described in.

Here, the cutting edge portion is a pair of first portions arranged at positions facing each other of the four corner portions of the front surface portion and the back surface portion via the center line of the fixing screw insertion hole. The first corner blade formed in the corner portion of the above is connected to the end portion (S1) of the first corner blade on the side surface portion in the short side direction, and along the crossing ridge line portion of the side surface portion in the short side direction. The main cutting edge having a linear shape formed in the above direction and the other end portion (S2) of the main cutting edge are connected to each other, and in a plan view of the front surface portion and the back surface portion, the main cutting edge is directed toward the outside of the side surface portion in the short side direction. It is arranged so as to gradually protrude in the direction of the fixing screw insertion hole with respect to the extension line of the main cutting edge as it is separated from the other end (S2) of the main cutting edge. It includes a first secondary cutting edge having an arc shape with a radius R, and a second secondary cutting edge having a linear shape connected to the other end (S3) of the first secondary cutting edge.

Further, the front surface portion and the back surface portion are provided with a reference flat surface portion formed so as to include the periphery of the opening of the fixing screw insertion hole. Further, in the cross-sectional view of the rake face of the second secondary cutting edge perpendicular to the cutting edge ridge line of the second secondary cutting edge, the cross-sectional ridge portion of the rake face of the second secondary cutting edge is the reference flat surface portion. It has a convex shape that protrudes upward from the front surface portion or the back surface portion with respect to the cross-sectional ridge line portion, and the front surface portion and the back surface portion serve as a rake face of the cutting edge portion and are continuous with the reference flat surface portion. It is equipped with a breaker surface. In the cutting insert described in Patent Document 1, the angle formed by the breaker surface portion on the first corner blade side and the reference flat surface portion is determined by the breaker surface portion on the second secondary cutting edge side and the reference. It is smaller than the angle formed by the flat surface.

Japanese Patent No. 5967330 (B)

By the way, in the cutting insert described in Patent Document 1, although the corner blade, the main cutting blade, and the first sub cutting blade are connected to the breaker surface portion via honing, a high hardness object such as HRC50 to 65 is used. When cutting a cutting material, the cutting edge strengths of these corner blades, main cutting blades, and first secondary cutting blades tend to be insufficient, which may cause defects. In particular, such a defect is likely to occur at the boundary between the work material and the corner blade even when the cutting amount of the corner blade into the work material is small.

The present invention has been made under such a background, and when cutting a high-hardness work material, it is possible to prevent the corner blade from being chipped regardless of the depth of cut. , And it is an object of the present invention to provide a cutting tool with a replaceable cutting edge to which such a cutting insert is detachably attached.

In order to solve the above problems and achieve such an object, the cutting insert of one aspect of the present invention (hereinafter, referred to as "cutting insert of the present invention") is an insert formed in a polygonal plate shape. A mounting hole that penetrates the insert body is opened on the front and back polygonal surfaces of the main body with the insert center line as the center, and in a plan view from the direction of the insert center line, the edge of the polygonal surface is formed. Is formed in the corner portion of the polygonal surface in a convex arc shape centered on the corner blade center line parallel to the insert center line, and from the corner blade first end portion of the corner blade. Is formed with a main cutting edge that extends linearly in the tangential direction of the corner blade, and the main cutting edge of the main cutting edge is formed from the first end of the main cutting edge opposite to the first end of the corner blade. A cutting insert in which a secondary cutting edge is formed that retracts with respect to an extension line toward the first end of the main cutting edge, and the polygonal surface is directed from the corner blade toward the inside of the polygonal surface. Therefore, a land portion that gradually protrudes in the direction of the insert center line is formed, and inside the polygonal surface, the land portion gradually recedes in the direction of the insert center line toward the inside of the polygonal surface. A rake face portion is formed, and the corner blade center line is formed along the corner blade from the first end portion of the corner blade toward the second end portion of the corner blade opposite to the first end portion of the corner blade. Within the range of 40 ° to the center, in the cross section along the corner blade center line, the inclination angle θ1 of the land portion with respect to the reference plane perpendicular to the insert center line is perpendicular to the insert center line of the rake face portion. It is characterized in that the inclination angle with respect to the reference plane is θ2 or more.

Further, the cutting tool with a replaceable cutting edge of another aspect of the present invention (hereinafter, referred to as "the cutting tool with a replaceable cutting edge of the present invention") is formed on the outer periphery of the tip portion of the tool body which is rotated in the tool rotation direction around the axis. On the insert mounting seat, such a cutting insert directs one of the polygonal surfaces in the direction of rotation of the tool, and uses the corner blade formed at the corner of the one polygonal surface as the tool body. The clamp screw inserted into the mounting hole is directed toward the outer peripheral side of the tip of the tool and the main cutting blade extending from the first end of the corner blade of the corner blade is directed toward the inner peripheral side of the tool body. It is characterized in that it is detachably attached by being screwed into the bottom surface of the insert attachment seat facing the tool rotation direction.
Further, the tool body of another aspect of the present invention (hereinafter, referred to as "tool body of the present invention") is a tool body for a cutting tool with a replaceable cutting edge, and is a tool that can be rotated in the tool rotation direction around the axis. The cutting insert of the present invention was formed on the insert mounting seat formed on the outer periphery of the tip portion of the main body at the corner portion of the one polygonal surface with the one said polygonal surface facing the tool rotation direction. The corner blade is directed toward the outer peripheral side of the tip of the tool body, and the main cutting blade extending from the first end of the corner blade of the corner blade is directed toward the inner peripheral side of the tool body in the mounting hole. A tool body characterized in that the inserted clamp screw is screwed into the bottom surface of the insert mounting seat facing the tool rotation direction so that the tool body can be detachably mounted.

In the cutting insert having the above configuration, a land portion that gradually protrudes in the direction of the insert center line from the corner blade toward the inside of the polygonal surface and a land portion that gradually protrudes toward the inside of the polygonal surface from the land portion are inserted into the polygonal surface. A rake face portion that gradually recedes in the direction of the center line is formed, and within a range of 40 ° around the center line of the corner blade from the first end of the corner blade to the second end of the corner blade along the corner blade. In the cross section along the corner blade center line, the inclination angle θ1 with respect to the reference plane perpendicular to the insert center line of the land portion is set to be equal to or greater than the inclination angle θ2 with respect to the reference plane perpendicular to the insert center line of the rake face portion. Within this range, it is possible to secure a large cross-sectional area of the cross section along the corner blade center line of the insert body on the polygonal surface connected to the corner blade.

That is, within the above range in which the corner blade is exclusively used for cutting, the thickness of the insert body on the polygonal surface connected to the corner blade can be increased to give high cutting edge strength, and the work has a high hardness. Even when the material is cut, the fracture resistance of the corner blade can be improved. Therefore, according to the cutting insert and the cutting tool with replaceable cutting edge configured in this way, it is possible to perform stable cutting for a long period of time even on such a high-hardness work material.

Here, between the land portion and the rake face portion, a convex curved top portion in contact with the land portion and the rake surface portion is formed in a cross section along the corner blade center line, and from the rake surface portion. Inside the polygonal surface, the insert centerline is directed toward the inside of the polygonal surface with respect to the extension line of the rake face portion to the inside of the polygonal surface in the cross section along the corner blade centerline. A rear wall surface portion that gradually recedes in the direction and a boss surface that is a plane perpendicular to the insert center line that extends from the rear wall surface portion to the inside of the polygonal surface and forms an opening of the mounting hole are formed. If so, the center of the corner blade is within a range of 40 ° from the first end of the corner blade toward the second end of the corner blade along the corner blade center line. In the cross section along the line, the distance H1 in the direction perpendicular to the corner blade center line from the corner blade to the apex of the top in the insert center line direction is the polygon of the rake face portion from the apex of the top. It is desirable that the distance H2 or less in the direction perpendicular to the center line of the corner blade to the intersection of the extension line inward of the surface and the boss surface is H2 or less.

With this configuration, the distance H2 is equal to or greater than the distance H1, so that a larger cross-sectional area of the cross section along the corner blade center line of the insert body on the polygonal surface connected to the corner blade can be secured. It is possible to give high cutting edge strength to the corner blade and further improve the fracture resistance.

In this case, the corner blade is within a range of 40 ° about the center line of the corner blade from the first end of the corner blade toward the second end of the corner blade along the corner blade. In the cross section along the center line, the distance H3 in the direction perpendicular to the corner blade center line from the apex of the apex to the contact point or the intersection of the rear wall surface and the boss surface, and the distance H3 from the apex of the apex to the apex. The ratio H3 / H2 to the distance H2 in the direction perpendicular to the corner blade center line to the intersection of the extension line of the rake face portion to the inside of the polygonal surface and the boss surface is in the range of 0.45 to 0.75. It is desirable to be inside.

With this configuration, it is possible to improve the discharge of chips generated during cutting, and as will be described later, when the insert body has a front-back inverted symmetrical shape, the insert mounting seat of the tool body The area of the boss surface, which is the seating surface that can be brought into close contact with the bottom surface facing the tool rotation direction, can be secured, and the cutting insert can be stably seated on the insert mounting seat.

That is, if this ratio H3 / H2 is smaller than 0.45, the contact distance between the chips and the rake face portion becomes short, so that the control of the chip discharge direction may become unstable. On the contrary, when the ratio H3 / H2 is larger than 0.75, the contact distance between the chips and the rake face portion becomes long, the cutting resistance due to the scraping of the chips increases, and the rear wall surface portion recedes inward of the polygonal surface. As described above, the area of the boss surface, which is the seating surface that is brought into close contact with the bottom surface of the insert mounting seat, becomes smaller, and the seating stability of the cutting insert may be impaired.

Further, as described above, the polygonal surface is inside the polygonal surface from the rake face portion, and the polygonal surface is an extension line of the rake face portion to the inside of the polygonal surface in a cross section along the corner blade center line. It is perpendicular to the rear wall surface portion that gradually recedes in the direction of the insert center line toward the inside of the insert, and the insert center line that extends from the rear wall surface portion to the inside of the polygonal surface to form an opening of the mounting hole. When a flat boss surface is formed, a range of 40 ° about the center line of the corner blade from the second end of the corner blade to the first end of the corner blade along the corner blade. Within, when the tangent line or the intersection line between the rear wall surface portion and the boss surface is formed in an arc shape in the plan view, the rear wall surface portion is formed with respect to the radius G1 of the arc formed by the corner blade in the plan view. It is desirable that the ratio G2 / G1 formed by the radius G2 of the arc formed by the tangent or intersection of the boss surface and the boss surface is within the range of 0.23 to 0.87.

That is, when this ratio G2 / G1 is smaller than 0.23, the width from the corner blade viewed from the corner blade center line direction to the tangent line or intersection line between the rear wall surface portion and the boss surface becomes large, and the chip and the land portion The contact distance with the easy surface becomes longer and the cutting resistance increases, and the rear wall surface recedes inside the polygonal surface to reduce the area of the boss surface, which may impair the seating stability of the cutting insert. be. On the contrary, when this ratio G2 / G1 is larger than 0.87, the width from the corner blade viewed from the corner blade center line direction to the tangent line or the intersection line between the rear wall surface portion and the boss surface becomes small, and the chips and chips are formed. Since the contact distance between the land portion and the easy surface portion is shortened, the control of the chip discharge direction may become unstable.

Further, by forming a region extending along the direction parallel to the reference plane perpendicular to the insert center line in the corner blade, in this region, the wall thickness of the insert body from the corner blade is also formed in the direction of the insert center line. Since it is possible to give high cutting edge strength, for example, even when cutting the machined surface of a work material with a large number of holes, it is possible to improve the fracture resistance of the corner blade. Can be done.

Furthermore, the polygonal surface is a rectangular surface formed 180 ° rotationally symmetric with respect to the insert center line, and two corner portions located on one diagonal line of the rectangular surface are arranged. By forming the corner blades and forming the main cutting blade and the sub cutting blade on the short side portion of the rectangular surface connected to the corner blades, two corner blades are formed on one polygonal surface. , Main cutting edge, and secondary cutting edge can be used, which is efficient and economical. In particular, in this case, by forming the insert body into a front-back inverted symmetrical shape, it is possible to use four sets of corner blades, main cutting blades, and auxiliary cutting blades in one insert body, and even more. Efficient and economical.

As described above, according to the present invention, since it is possible to give a high cutting edge strength to the corner blade, it is possible to improve the fracture resistance of the corner blade and to cut a work material having a high hardness. Even in this case, stable cutting can be performed for a long period of time.

It is a perspective view which shows the 1st Embodiment of the cutting insert of this invention. It is a top view which looked at the embodiment shown in FIG. 1 from the direction of the insert center line. It is a side view of the arrow line V direction view in FIG. It is a side view of the arrow line W direction view in FIG. FIG. 2 is an enlarged cross-sectional view of CX in FIG. FIG. 2 is an enlarged cross-sectional view taken along the line CY in FIG. FIG. 2 is an enlarged cross-sectional view of CZ in FIG. It is a perspective view of the tool body of the cutting tool of the cutting edge exchange type to which the embodiment shown in FIG. 1 is attached. It is a side view of the tool body shown in FIG. It is a perspective view which shows one Embodiment of the cutting edge exchange type cutting tool of this invention which attached the cutting insert of the embodiment shown in FIG. 1 to the tool body shown in FIG. It is a side view of the embodiment shown in FIG. It is a perspective view which shows the 2nd Embodiment of the cutting insert of this invention. It is a top view which looked at the embodiment shown in FIG. 12 from the direction of the insert center line. It is a side view of the arrow line V direction view in FIG. It is a side view of the arrow line W direction view in FIG. FIG. 13 is an enlarged cross-sectional view of CX in FIG. FIG. 13 is an enlarged cross-sectional view taken along the line CY in FIG. FIG. 13 is an enlarged cross-sectional view of CZ in FIG. It is a perspective view which shows the 3rd Embodiment of the cutting insert of this invention. It is a top view which looked at the embodiment shown in FIG. 19 from the direction of the insert center line. It is a side view of the arrow line V direction view in FIG. It is a side view of the arrow line W direction view in FIG. FIG. 2 is an enlarged cross-sectional view of CX in FIG. FIG. 2 is an enlarged cross-sectional view taken along the line CY in FIG. FIG. 2 is an enlarged cross-sectional view of CZ in FIG. It is a perspective view which shows the 4th Embodiment of the cutting insert of this invention. FIG. 6 is a plan view of the embodiment shown in FIG. 26 as viewed from the direction of the insert center line. It is a side view of the arrow line V direction view in FIG. 27. It is a side view of the arrow line W direction view in FIG. 27. FIG. 27 is an enlarged cross-sectional view of CX in FIG. 27. FIG. 27 is an enlarged cross-sectional view of CY in FIG. 27. FIG. 27 is an enlarged cross-sectional view of CZ in FIG. 27.

1 to 7 show a first embodiment of the cutting insert of the present invention. 8 and 9 show a tool body of a cutting tool with a replaceable cutting edge to which the cutting insert of the first embodiment is detachably attached, and FIGS. 10 and 11 show the tool body of the tool body. It shows one embodiment of the cutting tool with a replaceable cutting edge of the present invention to which the cutting insert of the first embodiment shown in FIGS. 1 to 7 is attached.

The cutting insert of the present embodiment includes an insert body 1 formed in a polygonal plate shape by a hard material such as cemented carbide, and the polygonal surface 2 of the insert body 1 is the center of the insert in the present embodiment. It is formed in a substantially rectangular plane shape centered on the line L. The insert center line L is a line that passes through the center of the polygonal surface 2 and is parallel to the thickness direction of the insert body. In the insert body 1, a mounting hole 1A having a circular cross section centered on the insert center line L is formed so as to penetrate the insert body 1 and opens at the center of the front and back polygonal surfaces 2.

As shown in FIG. 2 in a plan view seen from the insert center line L direction, the edge portion of the polygonal surface 2 of the insert body 1 is parallel to the insert center line L at the corner portion of the polygonal surface 2. A corner blade 3 having a convex arc shape centered on the center line C of the corner blade is formed. Further, the main cutting extending linearly in the tangential direction of the corner blade 3 from the corner blade first end 3a of the corner blade 3 (the end of the corner blade 3 on the short side side in the rectangle formed by the polygonal surface 2). The blade 4 is formed.

Further, an extension line of the main cutting blade 4 from the first end portion 4a of the main cutting blade on the side opposite to the first end portion 3a of the corner blade to the side of the first end portion 4a of the main cutting blade of the main cutting blade 4. A secondary cutting edge 5 that recedes inside the polygonal surface 2 is formed. In the present embodiment, the sub-cutting blade 5 has a convex arc shape having a larger radius than the corner blade 3 in the plan view, and is in contact with the main cutting blade 4 at the first end portion 4a of the main cutting blade. The cutting edge 5A and the secondary cutting edge 1st end 5a on the side opposite to the main cutting edge 1st end 4a of the 1st secondary cutting edge 5A come into contact with the 1st secondary cutting edge 5A and extend linearly. It is equipped with 2 secondary cutting blades 5B.

In the present embodiment, the rectangular surface formed by the front and back polygonal surfaces 2 is formed 180 ° rotationally symmetric with respect to the insert center line L, and two corner portions located on one diagonal line of this rectangular surface are formed. Corner blades 3 are formed in the arranged corner portions (lower right and upper left corner portions in FIG. 2). Further, the main cutting blade 4 and the sub cutting blade 5 are formed on the short side portion of the rectangular surface connected to the corner blade 3. Further, the insert body 1 of the present embodiment is formed in an inverted symmetrical shape, so that one insert body 1 is formed with four sets of corner blades 3, a main cutting blade 4, and a sub cutting blade 5.

Here, on the side surface of the insert body 1 extending between the front and back polygonal surfaces 2, a corner blade 3, a main cutting blade 4, and a flank 6 connected to the sub cutting blade 5 are formed. The side surface of the insert body 1 including the flank 6 extends parallel to the insert center line L, and the cutting insert of the present embodiment is a negative type cutting insert. Of the flanks 6, the portion of the sub-cutting blade 5 connected to the first sub-cutting blade 5A is a flank common to the first sub-cutting blades 5A formed on the same short side surface of the front and back polygonal surfaces 2. It is said that.

On the other hand, on the polygonal surface 2, the insert center extends toward the inside of the polygonal surface 2 as shown in FIGS. 5 to 7 over the entire length of the corner blade 3, the main cutting blade 4, and the sub cutting blade 5. A land portion 7 that gradually protrudes toward the outside of the insert body 1 in the line L direction is formed along the corner blade 3, the main cutting blade 4, and the sub cutting blade 5, and is more than the land portion 7. Inside the polygonal surface 2, a rake face portion 8 is formed that gradually recedes toward the inside of the insert body 1 in the direction of the insert center line L toward the inside of the polygonal surface 2. Further, between the land portion 7 and the rake face portion 8, the land portion 7 and the rake face portion 8 are formed in a cross section along the corner blade center line C and a cross section orthogonal to the main cutting blade 4 and the sub cutting blade 5. A convex curved top 9 in contact is formed.

Further, on the inside of the polygonal surface 2 than the rake face 8, as shown in FIGS. 5 to 7 in the cross section along the corner blade center line C, the rake face 8 is extended inward of the polygonal surface 2. A rear wall surface portion 10 is formed that gradually recedes in the insert center line L direction toward the inside of the polygonal surface 2 with respect to the line M. Further, on the inside of the polygonal surface 2 than the rear wall surface portion 10, the boss surface 2A which is a plane perpendicular to the insert center line L extending inward of the polygonal surface 2 and forming an opening of the mounting hole 1A is formed. Is formed.

Here, the land portion 7 may be formed linearly in a cross section along the corner blade center line C and a cross section orthogonal to the main cutting blade 4 and the sub cutting blade 5, but in the present embodiment, FIG. 5 As shown in FIG. 7, it is formed in a convex curve shape that is slightly convex in the corner blade center line C direction. Further, the rake face portion 8 may also be formed linearly in a cross section along the corner blade center line C and a cross section orthogonal to the main cutting blade 4 and the sub cutting blade 5, but in the present embodiment, the same is shown in FIG. As shown in FIG. 7, it is formed in a convex curve shape that is slightly convex in the corner blade center line C direction.

Furthermore, as shown in FIGS. 5 to 7, the rear wall surface portion 10 has a cross section along the corner blade center line C with respect to the extension line M of the rake face portion 8 which is linear as described later in the present embodiment. , A convex curve is formed toward the inside of the polygonal surface 2 and retracts in the insert center line L direction, and then a concave curve in contact with the convex curve is formed and retracts in the insert center line L direction so as to contact the boss surface 2A. Is formed in.

Then, the corner blade center line C is drawn from the corner blade first end portion 3a of the corner blade 3 toward the corner blade second end portion 3b on the side opposite to the corner blade first end portion 3a along the corner blade 3. Within the range of 40 ° to the center, as shown in FIGS. 5 to 7 in the cross section along the corner blade center line C, the inclination angle θ1 with respect to the reference plane P perpendicular to the insert center line L of the land portion 7 is raked. The inclination angle θ2 or more with respect to the reference surface P perpendicular to the insert center line L of the surface portion 8 is set. In FIGS. 5 to 7, the position of the reference surface P perpendicular to the insert center line L is aligned with the position of the boss surface 2A.

Further, in the cross section along the corner blade center line C, the inclination angle θ1 of the land portion 7 connected to the corner blade 3 shown in FIGS. 5 to 7 is preferably within the range of 15 ° to 25 °. In the embodiment, the angle is constant at 20 ° over the entire length of the corner blade 3.

On the other hand, in the cross section along the corner blade center line C, the inclination angle θ2 of the rake face portion 8 at the corner blade first end portion 3a shown in FIG. 7 is 17.1 °, and the corner blade first shown in FIG. The position is 40 ° around the center line C of the corner blade from the first end 3a toward the second end 3b of the corner blade, and the corner blade is located from the second end 3b of the corner blade toward the first end 3a of the corner blade. The inclination angle θ2 of the rake face portion 8 at a position that is also 40 ° around the center line C is 16.4 °, and the inclination angle θ2 of the rake face portion 8 at the second end portion 3b of the corner blade 3 of the corner blade 3 shown in FIG. It is said to be 14.4 °. That is, in the present embodiment, the corner blade center line C is centered from the corner blade second end 3b on the side opposite to the corner blade first end 3a along the corner blade 3 toward the corner blade first end 3a. Even within the range of 40 °, the inclination angle θ1 with respect to the reference plane P perpendicular to the insert center line L of the land portion 7 is perpendicular to the insert center line L of the rake face portion 8 in the cross section along the corner blade center line C. The inclination angle θ2 with respect to the reference surface P is set, and the inclination angle θ1 of the land portion 7 is set to the inclination angle θ2 or more of the rake face portion 8 over the entire length of the corner blade 3, and in particular, the inclination angle θ1 is made larger than the inclination angle θ2. ing. It is desirable that the inclination angle θ2 of the rake face portion 8 connected to the corner blade 3 via the land portion 7 and the top portion 9 is within the range of 5 ° to 20 °.

Here, in the present embodiment, the cross section of the land portion 7 along the corner blade center line C has a convex curved shape that is slightly convex as described above, so that the inclination angle θ1 of the land portion 7 is determined. As shown in FIGS. 5 to 7, in a cross section along the corner blade center line C, the straight line N connecting the corner blade 3 and the apex 9a most protruding in the insert center line L direction of the top portion 9 with respect to the reference surface P. It is said to be an inclination angle. However, when the land portion 7 is formed in a straight line in the cross section along the corner blade center line C as described above, the inclination angle θ1 of the land portion 7 is the inclination angle of this straight line with respect to the reference surface P. do it.

Further, in the present embodiment, the rake face portion 8 also has a convex curved shape in which the cross section along the corner blade center line C is slightly convex as described above, so that the inclination angle θ2 of the rake face portion 8 is determined. As shown in FIGS. 5 to 7, in the cross section along the corner blade center line C, the apex 9a of the top portion 9 and the rake face portion 8 where the rear wall surface portion 10 starts to recede in the insert center line L direction from the rake face portion 8. The inclination angle of the straight line connecting the contact point 8a with the rear wall surface portion 10 with respect to the reference surface P, that is, the intersection angle between the extension line M of this straight line inward of the polygonal surface 2 and the reference surface P (boss surface 2A). Will be done.

However, when the rake face portion 8 also has a straight line in the cross section along the corner blade center line C as described above, the inclination angle θ2 of the rake face portion 8 with respect to the reference plane P of this straight line. The inclination angle, that is, the intersection angle between the extension line M and the reference surface P inward of the straight polygonal surface 2 formed by the rake face portion 8 in the cross section along the corner blade center line C may be used.

Further, in the present embodiment, the corner blade center line is within a range of 40 ° about the corner blade center line C from the corner blade first end portion 3a to the corner blade second end portion 3b along the corner blade 3. As shown in FIGS. 5 to 7 in the cross section along C, the distance H1 in the direction perpendicular to the corner blade center line C from the corner blade 3 to the apex 9a in the insert center line L direction of the top 9 is the top. The distance H2 or less in the direction perpendicular to the corner blade center line C from the apex 9a of 9 to the intersection 2a of the extension line M and the boss surface 2A inward of the polygonal surface 2 of the rake face portion 8 is set.

However, as in the present embodiment, when the rake face portion 8 is also formed in a convex curve shape slightly convex in the corner blade center line C direction in the cross section along the corner blade center line C, the rake face portion 8 is also formed. The extension line to the inside of the polygonal surface 2 of the above is also a convex curve that is slightly convex in the corner blade center line C direction.

Therefore, in such a case, as shown in FIGS. 5 to 7, the distance H2 is such that the rake face portion 8 and the rear wall surface portion 10 start to recede in the insert center line L direction from the rake face portion 8. Corner blade center line from the apex 9a of the apex 9 to the intersection of the extension line M inward of the polygonal surface 2 in the straight line connecting the contact point 8a and the apex 9a of the apex 9 and the boss surface 2A. The distance may be the direction perpendicular to C.

Furthermore, in the present embodiment, the corner blade center is within a range of 40 ° about the corner blade center line C from the corner blade first end portion 3a to the corner blade second end portion 3b along the corner blade 3. As shown in FIGS. 5 to 7 in the cross section along the line C, the corner blade from the apex 9a of the top portion 9 to the contact point or intersection (contact point 10a in the present embodiment) with the boss surface 2A of the rear wall surface portion 10. To the distance H3 in the direction perpendicular to the center line C and the corner blade center line C from the apex 9a of the top portion 9 to the intersection point 2a of the extension line M and the boss surface 2A inward of the polygonal surface 2 of the rake face portion 8. The ratio H3 / H2 to the distance H2 in the vertical direction is in the range of 0.45 to 0.75.

In particular, it is desirable that the distance H1 at the first end 3a of the corner blade is within the range of 0.35 mm to 0.45 mm, and in the present embodiment, the distance H1 is 0.4 mm over the entire length of the corner blade 3. It is constant. On the other hand, the distance H2 at the corner blade first end 3a shown in FIG. 7 is 1.1 mm and the distance H3 is 0.8 mm, and the corner blade first end 3a to the corner blade second end shown in FIG. The distance H2 at a position 40 ° around the corner blade center line C toward the portion 3b is 1.2 mm, the distance H3 is 0.7 mm, and the distance of the corner blade 3 shown in FIG. 5 at the second end 3b of the corner blade. H2 is 0.7 mm and the distance H3 is 0.4 mm.

That is, in the present embodiment, the distance H1 is a distance along the corner blade 3 from the corner blade second end 3b toward the corner blade first end 3a even within a range of 40 ° about the corner blade center line C. It is set to H2 or less, and the distance H1 is set to the distance H2 or less over the entire length of the corner blade 3. Further, the ratio H3 / H2 is 0.45 to 0 within a range of 40 ° about the corner blade center line C from the corner blade first end 3a to the corner blade second end 3b along the corner blade 3. The ratio is within the range of .75, and even within the range of 40 ° around the corner blade center line C from the corner blade second end 3b to the corner blade first end 3a along the corner blade 3. H3 / H2 is in the range of 0.45 to 0.75.

Further, in the present embodiment, the rear wall surface portion 10 is within a range of 40 ° about the corner blade center line C from the corner blade second end portion 3b toward the corner blade first end portion 3a along the corner blade 3. The tangent line or line of intersection (tangent line Q in this embodiment) between the boss surface 2A and the boss surface 2A is formed in an arc shape as shown in FIG. 2 in the plan view. Then, in this plan view, the ratio G2 / G1 formed by the radius G2 of the arc of the tangent line Q between the rear wall surface portion 10 and the boss surface 2A with respect to the radius G1 of the arc formed by the corner blade 3 is 0. It is in the range of 23 to 0.87.

On the other hand, in the present embodiment, the corner blade 3 is formed with a parallel region A extending in a direction parallel to the reference plane P perpendicular to the insert center line L. Here, as shown in FIG. 4, the corner blade 3 in the present embodiment is located at a position close to the boss surface 2A in the insert center line L direction at the corner blade second end portion 3b.

Then, the corner blade 3 gradually protrudes in the insert center line L direction as shown in FIG. 4 from the corner blade second end 3b toward the corner blade first end 3a, and from the corner blade second end 3b. It extends toward the first end 3a of the corner blade and is parallel to the reference plane P perpendicular to the center line L of the insert at a position 40 ° from the second end 3b of the corner blade around the center line C of the corner blade. It reaches the parallel region A extending along the above direction. Further, after reaching the parallel region A, the corner blade 3 extends in a direction parallel to the reference surface P, reaches the first end portion 3a of the corner blade, and is connected to the main cutting blade 4.

Further, in the present embodiment, the main cutting blade 4 in which the corner blades 3 are connected and the first secondary cutting blade 5A on the main cutting blade 4 side among the secondary cutting blades 5 connected to the main cutting blade 4 are also shown in FIG. As shown in the above, the corner blade is located on the parallel region A extending in the direction parallel to the reference plane P perpendicular to the insert center line L through the first end portion 3a of the corner blade. On the other hand, in the present embodiment, the second sub-cutting blade 5B connected to the first sub-cutting blade 5A has an insert center line toward the second end portion 5b of the sub-cutting blade opposite to the first end portion 5a of the sub-cutting blade. It is provided with an inclined region B that gradually recedes in the L direction.

Here, in the present embodiment, as shown in FIG. 3, the portion of the second secondary cutting edge 5B on the side of the first end portion 5a of the secondary cutting edge is in a direction parallel to the reference plane P perpendicular to the insert center line L. It is a parallel region A extending along. Then, the portion of the secondary cutting edge 2nd end 5b side of the parallel region A draws a convex curve that becomes convex in the insert center line L direction toward the secondary cutting edge 2nd end 5b side, and the insert center. It is defined as an inclined region B that recedes in the line L direction and then gradually recedes in the insert center line L direction at a constant inclination angle.

Further, as shown in FIG. 3 when viewed from the direction facing the flank 6 of the secondary cutting edge 5, the width W1 in the direction perpendicular to the insert center line L of the inclined region B in the second secondary cutting edge 5B is the present implementation. In the embodiment, the width W2 in the direction perpendicular to the insert center line L of the parallel region A in the second secondary cutting edge 5B is made larger.

Further, although not shown, it is desirable that the inclination angle θ1 of the land portion 7 in the cross section orthogonal to the sub cutting edge 5 at the first end portion 5a of the sub cutting edge is within the range of 15 ° to 35 °. In the embodiment, it is set to 20 °. Similarly, at the first end portion 5a of the secondary cutting edge, the distance in the direction perpendicular to the insert center line L of the land portion 7 in the cross section orthogonal to the secondary cutting edge 5 is within the range of 0.15 mm to 0.45 mm. Is desirable, and is set to 0.4 mm in this embodiment.

Here, the insert body 1 of the cutting insert formed of such a hard material such as cemented carbide is manufactured according to the basic process of powder metallurgy technology. That is, when the insert body 1 is made of cemented carbide, a mold is used by using a granular granulated powder containing tungsten carbide powder and cobalt powder as main components and chromium, tantalum and the like as subcomponents as necessary. Perform powder press molding using.

The press-formed body thus obtained can be sintered for a predetermined time in a sintering furnace controlled to an appropriate atmosphere and temperature to produce a sintered body to be the insert body 1. The basic shape of the insert body 1 is reflected by the design of the mold, and the detailed shape of the insert body 1 is obtained by mold molding. Further, in order to improve the accuracy of the cutting edge shape of the insert body 1, grinding processing using a grinding wheel may be performed as necessary.

The cutting insert having such a configuration is detachably attached to the insert mounting seat 12 formed on the outer periphery of the tip end portion of the tool body 11 of the cutting tool with replaceable cutting edge shown in FIGS. 8 and 9, and is detachably attached to FIGS. 10 and 11. It constitutes an embodiment of the cutting tool with a replaceable cutting edge of the present invention shown in the above. The cutting insert thus attached to the insert mounting seat 12 is sent out in a direction intersecting the axis O while the tool body 11 is rotated around the axis O in the tool rotation direction T, whereby the corner blade 3 and the main cutting blade are fed. The work material is cut by the 4 and the secondary cutting edge 5.

The tool body 11 is integrally formed of a metal material such as a steel material in a substantially cylindrical shaft shape centered on the axis O, and the rear end portion (upper portion in FIGS. 8 to 11) is a shank portion that remains cylindrical. The tip portion (lower portion in FIGS. 8 to 11) is a cutting edge portion 11B having a diameter smaller than that of the shank portion 11A, and the insert mounting seat 12 is formed on the cutting edge portion 11B. ing. Further, between the shank portion 11A and the cutting edge portion 11B, a tapered neck portion 11C whose diameter is reduced toward the tip end side of the tool body 11 is formed.

A plurality of recessed groove-shaped tip pockets 13 (four at equal intervals in the circumferential direction) are formed on the outer periphery of the cutting edge portion 11B of the tool body 11 at intervals in the circumferential direction. The insert mounting seat 12 is formed at the tip of the wall surface of these tip pockets 13 facing the tool rotation direction T as a recess recessed on the side opposite to the tool rotation direction T. A coolant hole 11a formed in the tool body 11 is opened on the wall surface of the tip pocket 13 facing the side opposite to the tool rotation direction T.

The insert mounting seat 12 is formed on a bottom surface 12a facing the tool rotation direction T, a wall surface 12b extending from the inner peripheral side of the bottom surface 12a in the tool body 11 in the tool rotation direction T and facing the outer peripheral side, and a tool body 11 on the bottom surface 12a. It is provided with a wall surface 12c extending from the rear end side in the tool rotation direction T and facing the front end side. Further, a concave groove-shaped relief portion 12d is formed at a corner portion where the bottom surface 12a and the wall surfaces 12b and 12c intersect with each other and at a corner portion where the wall surfaces 12b and 12c intersect with each other.

The bottom surface 12a is formed in a plane shape having a similar shape that is one size smaller than the boss surface 2A of the polygonal surface 2 of the insert body 1 of the cutting insert, and is on the T side in the tool rotation direction toward the rear end side of the tool body 11. It is slightly inclined toward. Further, a screw hole 12e is formed perpendicularly to the bottom surface 12a in the central portion of the bottom surface 12a.

In such an insert mounting seat 12, in the cutting insert of the above embodiment, one polygonal surface 2 of the insert body 1 is directed in the tool rotation direction T, and the boss surface 2A of the other polygonal surface 2 is in close contact with the bottom surface 12a. The corner blade 3 formed in one corner portion of the one polygonal surface 2 is directed toward the outer peripheral side of the tip of the tool body 11, and the main cutting blade extending from the corner blade first end portion 3a of the corner blade 3 is directed. 4 is seated so as to face the inner peripheral side of the tool body 11. At this time, the two side surfaces of the insert body 1 intersecting the other corner portion located on the diagonal line of the one polygonal surface 2 with the one corner portion are brought into contact with the wall surfaces 12b and 12c. ..

Then, in the cutting insert seated in this way, the clamp screw 14 inserted into the mounting hole 1A from the tool rotation direction T side is screwed into the screw hole 12e of the bottom surface 12a, so that the boss surface 2A of the other polygonal surface 2 Is pressed against the bottom surface 12a, and the two side surfaces intersecting the other corner portion of the one polygonal surface 2 are pressed against the wall surfaces 12b and 12c to be detachably attached to the insert mounting seat 12.

Since the bottom surface 12a of the cutting insert attached to the insert mounting seat 12 is inclined as described above, the rear end side of the tool body 11 as the insert center line L faces the side opposite to the tool rotation direction T. The corner blade 3 is slightly tilted toward the outer peripheral side of the tip of the tool body 11, and the flanks of the main cutting blade 4 and the sub cutting blade 5 extending from the corner blade 3 to the inner peripheral side of the tool body 11 A clearance angle is given to 6.

Further, the main cutting blade 4 extending from the corner blade 3 directed toward the outer peripheral side of the tip of the tool body 11 toward the inner peripheral side of the tool body 11 is slightly directed toward the tip end side of the tool body 11 toward the inner peripheral side. Can be tilted to. That is, the cutting tool with a replaceable cutting edge of the present embodiment is a radius end mill with a replaceable cutting edge. Further, the auxiliary cutting edge 5 connected to the main cutting edge 4 is positioned on a plane in which the straight line connecting the first end portion 4a of the main cutting edge and the first end portion 5a of the auxiliary cutting edge is perpendicular to the axis O of the tool body 11. It is arranged so as to.

In the cutting insert having the above configuration attached to the tool body 11 of the cutting tool with a replaceable cutting edge in this way, as described above, the insert center is formed on the polygonal surface 2 from the corner blade 3 toward the inside of the polygonal surface 2. A land portion 7 that gradually protrudes in the line L direction and a rake face portion 8 that gradually recedes in the insert center line L direction toward the inside of the polygonal surface 2 from the land portion 7 are formed.

Then, along the corner blade 3, from the corner blade first end portion 3a toward the corner blade second end portion 3b, within a range of 40 ° about the corner blade center line C, along the corner blade center line C. In the cross section, the inclination angle θ1 with respect to the reference surface P perpendicular to the insert center line L of the land portion 7 is set to be equal to or greater than the inclination angle θ2 with respect to the reference surface P perpendicular to the insert center line L of the rake face portion 8.

Therefore, in the cutting insert and the cutting tool with replaceable cutting edge configured as described above, the corners of the corner blade 3 used exclusively for cutting are cornered from the first end 3a of the corner blade to the second end 3b of the corner blade. Within a range of 40 ° around the blade center line C, secure a large cross-sectional area of the cross section of the insert body 1 on the polygonal surface 2 connected to the corner blade 3 along the corner blade center line C, especially on the corner blade 3 side. be able to.

Therefore, since the thickness of the insert body 1 on the polygonal surface 2 connected to the corner blade 3 can be increased to provide high cutting edge strength, the fracture resistance of the corner blade 3 can be improved and the value is high. Even when cutting a work material with hardness, stable cutting can be performed for a long period of time. In particular, in the present embodiment, the inclination angle θ1 is said to be such that the inclination angle θ1 is within a range of 40 ° around the corner blade center line C from the corner blade second end 3b toward the corner blade first end 3a along the corner blade 3. Since the inclination angle θ2 or more, that is, the inclination angle θ1 is set to the inclination angle θ2 or more over the entire length of the corner blade 3, the resistance of the corner blade 3 even when the entire length of the corner blade 3 is used. Deficiency can be improved.

Further, in the present embodiment, a convex curved top portion 9 in contact with the land portion 7 and the rake face portion 8 is formed between the land portion 7 and the rake face portion 8 in a cross section along the corner blade center line C. At the same time, inside the polygonal surface 2 than the rake face portion 8, the inside of the polygonal surface 2 with respect to the extension line M of the rake face portion 8 to the inside of the polygonal surface 2 in the cross section along the corner blade center line C. It is perpendicular to the rear wall surface portion 10 that gradually recedes in the direction of the insert center line L toward the direction of A boss surface 2A which is a plane P is formed.

Then, along the corner blade 3, from the corner blade first end portion 3a toward the corner blade second end portion 3b, within the above range of 40 ° about the corner blade center line C, along the corner blade center line C. In the cross section, the distance H1 in the direction perpendicular to the corner blade center line C from the corner blade 3 to the apex 9a in the insert center line L direction of the top 9 is inside the polygonal surface 2 of the rake face 8 from the apex 9a of the top 9. The distance H2 or less in the direction perpendicular to the corner blade center line C up to the intersection 2a between the extension line M and the boss surface 2A.

Therefore, according to the present embodiment, the distance H2 from the top portion 9 arranged inside the polygonal surface 2 of the land portion 7 to the extension line M reaching the boss surface 2A along the rake face portion 8 is the land. The distance is H1 or more, which is the width of the portion 7. Therefore, it is possible to secure a larger cross-sectional area of the cross section of the insert body 1 on the polygonal surface 2 connected to the corner blade 3 along the corner blade center line C, and give the corner blade 3 even higher cutting edge strength. This makes it possible to improve the fracture resistance more reliably. In this embodiment, the distance H1 which is the width of the land portion 7 is constant from the corner blade second end portion 3b to the main cutting blade first end portion 4a.

Further, in the present embodiment, the corner blade center is within the above range of 40 ° about the corner blade center line C from the corner blade first end portion 3a to the corner blade second end portion 3b along the corner blade 3. In the cross section along the line C, the distance H3 in the direction perpendicular to the corner blade center line C from the apex 9a of the apex 9 to the contact point 10a between the rear wall surface 10 and the boss surface 2A and the apex 9a of the apex 9 The ratio H3 / H2 to the distance H2 in the direction perpendicular to the corner blade center line C up to the intersection 2a between the extension line M of the polygonal surface 2 of the rake face portion 8 and the boss surface 2A is 0.45 to 0. It is within the range of .75.

Therefore, it is possible to improve the dischargeability of chips generated by the corner blade 3, the main cutting blade 4, and the sub cutting blade 5 during cutting, and the insert body 1 is turned upside down as in the present embodiment. When the shape is symmetrical, a large area of the boss surface 2A, which is the seating surface to be brought into close contact with the bottom surface 12a of the insert mounting seat 12 of the tool body 11, is secured so that the cutting insert can be stably seated on the insert mounting seat 12. It becomes possible to make it.

Here, if this ratio H3 / H2 is smaller than 0.45, the contact distance between the chips and the rake face portion 8 becomes short, so that the control of the chip discharge direction may become unstable. Further, when this ratio H3 / H2 is larger than 0.75, on the contrary, the contact distance between the chips and the rake face portion 8 becomes long, the cutting resistance due to the scraping of the chips increases, and the rear wall surface portion 10 has a polygonal surface. Since it retracts inward, the area of the boss surface 2A of the polygonal surface 2 which is the seating surface to be brought into close contact with the bottom surface 12a of the insert mounting seat 12 becomes smaller as described above, and the seating stability of the cutting insert is improved. It may be damaged.

Furthermore, in the present embodiment, the rear wall surface is within a range of 40 ° about the corner blade center line C from the corner blade second end 3b toward the corner blade first end 3a along the corner blade 3. The tangent line Q between the portion 10 and the boss surface 2A is formed in a concave arc shape in the plan view. Then, in the plan view, the ratio G2 / G1 formed by the radius G2 of the concave arc of the tangent line Q between the rear wall surface portion 10 and the boss surface 2A is 0.23 to 0. It is said to be within the range of 87.

Therefore, the seating stability of the cutting insert can be improved, and the chip discharge direction can be easily controlled. That is, if this ratio G2 / G1 is smaller than 0.23, the rear wall surface portion 10 recedes inward of the polygonal surface 2 and the area of the boss surface 2A becomes small, which may impair the seating stability of the cutting insert. In addition, the width from the corner blade 3 seen from the corner blade center line C direction to the tangent line Q between the rear wall surface portion 10 and the boss surface 2A becomes large, and the contact distance between the chip and the land portion 7 and the easy surface portion 8 increases. It may become longer and the cutting resistance may increase.

On the contrary, when this ratio G2 / G1 is larger than 0.87, the width from the corner blade 3 viewed from the corner blade center line C direction to the tangent line Q between the rear wall surface portion 10 and the boss surface 2A becomes small. Since the contact distance between the chips and the easy-to-use surface portion 8 of the land portion 7 is shortened, the control of the chip discharge direction may become unstable.

In the present embodiment, since the rear wall surface portion 10 is in contact with the boss surface 2A, the distance H3 and the radius G2 are based on the contact points 10a and the tangent line Q between the boss surface 2A and the rear wall surface portion 10. However, when the rear wall surface portion 10 intersects the boss surface 2A at an angle, it may be based on the intersection or line of intersection between the boss surface 2A and the rear wall surface portion 10.

Further, in the present embodiment, the polygonal surface 2 is a rectangular surface formed 180 ° rotationally symmetric with respect to the insert center line L, and two corners located on one diagonal line of the rectangular surface. Since the corner blade 3 is formed in the corner portion where the portion is arranged, and the main cutting blade 4 and the sub cutting blade 5 are formed in the short side portion of the rectangular surface connected to the corner blade 3, one is formed. Two corner blades 3, a main cutting blade 4, and a secondary cutting blade 5 can be used on the polygonal surface 2, which is efficient and economical.

Moreover, in the present embodiment, the insert body 1 having such a rectangular surface-shaped polygonal surface 2 has a front-back inverted symmetrical shape. Therefore, four sets of corner blades 3 and a main cutting blade are formed in one insert body 1. Since 4 and the secondary cutting edge 5 can be used, it is even more efficient and economical.

On the other hand, in the present embodiment, the corner blade 3 is formed with a parallel region A extending in a direction parallel to the reference plane P perpendicular to the insert center line C. In this parallel region A, the insert center line L is formed. The wall thickness of the insert body 1 from the corner blade 3 can be increased also in the direction. Therefore, since it is possible to give a high cutting edge strength to the corner blade 3, for example, even when cutting a machined surface of a work material having a large number of holes, the fracture resistance of the corner blade 3 is further improved. Can be made to.

Further, in the present embodiment, the corner blade 3 extending along the parallel region A, the main cutting blade 4 connected at the corner blade first end portion 3a, and the main cutting blade 4 at the main cutting blade first end portion 4a. Of the continuous sub-cutting blades 5, the first sub-cutting blade 5A on the main cutting edge 4 side also has a parallel region extending along the direction parallel to the reference plane P perpendicular to the insert center line L through the corner blade first end 3a. It is located on A. Therefore, also in the first auxiliary cutting edge 5A of the main cutting edge 4 and the auxiliary cutting edge 5, the wall thickness in the insert center line L direction can be secured and the cutting edge strength can be improved, and a large number of holes are formed. High fracture resistance can be obtained in cutting of work materials and the like.

Moreover, in the present embodiment, the portion of the secondary cutting edge 5 on the side of the secondary cutting edge 1st end 5a of the second secondary cutting edge 5B connected to the first secondary cutting edge 5A at the secondary cutting edge 1st end 5a is also a corner. Since it is located on the parallel region A extending in the direction parallel to the reference plane P perpendicular to the insert center line L through the first end portion 3a of the blade, it has a fracture resistance even when the feed amount per blade is large. It becomes possible to improve. Even if the parallel region A is not located exactly parallel to the reference plane P perpendicular to the insert center line L, it is within 0.5 ° with respect to the reference plane P, for example, within the range of manufacturing error. There may be an angle error.

On the other hand, in the sub-cutting blade 5, the second sub-cutting blade 5B connected to the first sub-cutting blade 5A is the sub-cutting blade second end portion 5b on the side opposite to the sub-cutting blade first end portion 5a in the present embodiment. It is provided with an inclined region B that gradually recedes in the direction of the insert center line L toward the direction of. Here, the second secondary cutting edge 5B is slightly inclined toward the rear end side toward the inner peripheral side of the tool body 11 with the insert body 1 attached to the insert mounting seat 12. , Is used exclusively when performing an inclined cutting process in which the tool body 11 is sent obliquely with respect to the axis O. Therefore, according to the present embodiment, even in the case of such inclined cutting, the fracture resistance of the second secondary cutting edge 5B can be improved.

Moreover, in the present embodiment, the width W1 in the direction perpendicular to the insert center line L of the inclined region B in the second secondary cutting edge 5B when viewed from the direction facing the flank 6 of the secondary cutting edge 5 is the second secondary. The width W2 in the direction perpendicular to the insert center line L of the parallel region A in the cutting edge 5B is made larger. Therefore, even when the cutting amount is large in the inclined cutting process as described above, the fracture resistance of the second secondary cutting edge 5B can be more reliably ensured.

Further, in the present embodiment, in the cross section along the corner blade center line C, the inclination angle θ1 of the land portion 7 connected to the corner blade 3 is within the range of 15 ° to 25 °, which is the corner blade. The same applies to the first end portion 3a of the corner blade, which is the boundary between 3 and the main cutting blade 4. Therefore, at the corner blade first end portion 3a which is the boundary between the corner blade 3 and the main cutting blade 4, the fracture resistance can be maintained while reducing the cutting resistance.

That is, when the inclination angle θ1 of the land portion 7 at the first end portion 3a of the corner blade is less than 15 °, the blade angle becomes small and it is difficult to secure the fracture resistance in the cutting process of the high hardness work material. There is a risk of becoming. On the other hand, if the inclination angle θ1 of the land portion 7 at the first end portion 3a of the corner blade exceeds 25 °, the land portion 7 may rise too much and increase the cutting resistance.

Further, in the present embodiment, the distance H1 at the first end 3a of the corner blade, which is the boundary between the corner blade 3 and the main cutting blade 4, is within the range of 0.35 mm to 0.45 mm. At the corner blade first end portion 3a, which is the boundary between the corner blade 3 and the main cutting blade 4, the fracture resistance can be maintained while reducing the cutting resistance.

That is, when the distance H1 of the land portion 7 at the first end portion 3a of the corner blade is less than 0.35 mm, the land portion 7 becomes narrow and the fracture resistance in the cutting process of the high hardness work material is ensured. It can be difficult to do. On the other hand, if the distance H1 of the land portion 7 at the first end portion 3a of the corner blade exceeds 0.45 mm, the land portion 7 may become long and the cutting resistance may increase due to the contact of chips.

Furthermore, in the present embodiment, a land in a cross section orthogonal to the sub cutting edge 5 at the first end portion 5a of the sub cutting edge, which is a boundary between the first sub cutting edge 5A and the second sub cutting edge 5B of the sub cutting edge 5. The inclination angle θ1 of the portion 7 is within the range of 15 ° to 35 °. Therefore, it is possible to improve the fracture resistance at the first end 3a of the corner blade and promote the reduction of cutting resistance.

That is, when the inclination angle θ1 of the land portion 7 at the first end portion 5a of the secondary cutting blade is less than 15 °, the blade angle of the secondary cutting blade 5 becomes small and is damaged when cutting a high-hardness work material. Is likely to occur. On the other hand, if the inclination angle θ1 of the land portion 7 at the first end portion 5a of the secondary cutting edge exceeds 35 °, the land portion 7 of the secondary cutting edge 5 may rise too much, leading to an increase in cutting resistance. ..

Further, in the present embodiment, the distance in the direction perpendicular to the insert center line L of the land portion 7 in the cross section orthogonal to the sub cutting edge 5 at the first end portion 5a of the sub cutting edge is also in the range of 0.15 mm to 0.45 mm. This also makes it possible to improve the fracture resistance at the first end 3a of the corner blade and promote the reduction of cutting resistance.

That is, when the distance of the land portion 7 in the first end portion 5a of the secondary cutting edge in the direction perpendicular to the insert center line L is less than 0.15 mm, the land portion 7 becomes short and a high-hardness work material is cut. When doing so, defects are likely to occur. On the other hand, if the distance in the direction perpendicular to the insert center line L of the land portion 7 at the first end portion 5a of the secondary cutting blade exceeds 0.45 mm, the land portion 7 of the secondary cutting blade 5 also becomes too long. There is a risk of increasing cutting resistance due to contact with chips.

Next, FIGS. 12 to 18 show a second embodiment of the cutting insert of the present invention, and FIGS. 19 to 25 show a third embodiment of the cutting insert of the present invention. 26 to 32 show a fourth embodiment of the cutting insert of the present invention. In these cutting inserts of the second to fourth embodiments, the same reference numerals are given to the parts common to the cutting inserts of the first embodiment of the present invention shown in FIGS. 1 to 7, and the description thereof will be omitted. do.

In the cutting insert of the second embodiment shown in FIGS. 12 to 18, the inclination angle θ2 of the rake face portion 8 at the corner blade first end portion 3a shown in FIG. 18 is 17. The distance H3 is set to 0 ° and the distance H3 is set to 0.9 mm, and 40 ° around the corner blade center line C from the corner blade first end 3a shown in FIG. 17 toward the corner blade second end 3b. The inclination angle θ2 of the rake face portion 8 at the position of is 16.3 °, and the inclination angle θ2 of the rake face portion 8 at the corner blade second end 3b of the corner blade 3 shown in FIG. 16 is 14.2 °. The distance H2 is 0.8 mm. The specifications other than these are the same as those in the first embodiment.

Further, in the cutting inserts of the third embodiment shown in FIGS. 19 to 25, in the cross section along the corner blade center line C, the inclination angle θ1 of the land portion 7 at the corner blade first end portion 3a shown in FIG. 25 is The inclination angle θ2 of the rake face portion 8 is 20 °, the distance H2 is 1.1 mm, and the corner blade center line is from the corner blade first end 3a shown in FIG. 24 toward the corner blade second end 3b. The inclination angle θ2 of the rake face portion 8 at a position of 40 ° around C is 16.9 °, the distance H2 is 1.1 mm, and the distance H3 is 0.8 mm. The inclination angle θ1 of the land portion 7 at the two end portions 3b is 20 °, the inclination angle θ2 of the rake face portion 8 is 9.3 °, the distance H2 is 1.3 mm, and the distance H3 is 0.5 mm. The specifications other than these are the same as those in the first embodiment.

Further, in the cutting insert of the fourth embodiment shown in FIGS. 26 to 32, the inclination angle θ2 of the rake face portion 8 at the corner blade first end portion 3a shown in FIG. 32 is 16.9 °, and the distance H2 is 1. It is set to 1 mm, and the inclination angle θ2 of the rake face portion 8 at a position 40 ° around the corner blade center line C from the corner blade first end portion 3a to the corner blade second end portion 3b shown in FIG. 31 is 16.9 °. The distance H2 is 1.1 mm, the distance H3 is 0.8 mm, the inclination angle θ1 of the land portion 7 at the corner blade second end 3b of the corner blade 3 shown in FIG. 30 is 20 °, and that of the rake face portion 8. The inclination angle θ2 is 11.5 °, the distance H2 is 1.0 mm, and the distance H3 is 0.5 mm. The specifications other than these are the same as those in the first embodiment.

Also in such cutting inserts of the second to fourth embodiments, the inclination angle θ1 of the land portion 7 is set to be equal to or greater than the inclination angle θ2 of the rake face portion 8, so that the same effect as that of the first embodiment is obtained. Can be obtained. However, in the third and fourth embodiments, the direction perpendicular to the insert center line L of the inclined region B in the second secondary cutting edge 5B when viewed from the direction facing the flank 6 of the secondary cutting edge 5. The width W1 is not made larger than the width W2 in the direction perpendicular to the insert center line L of the parallel region A in the second secondary cutting edge 5B, and is substantially equal to or the insert of the inclined region B in the second secondary cutting edge 5B. The width W1 in the direction perpendicular to the center line L is made smaller than the width W2 in the direction perpendicular to the insert center line L of the parallel region A in the second secondary cutting edge 5B.

Even when cutting a high-hardness work material using a cutting tool with a replaceable cutting edge, stable cutting can be performed for a long period of time.

1 Insert body 1A Mounting hole 2 Polygonal surface 2A Boss surface 2a Extension line M and boss surface 2A from the apex 9a of the top 9 to the inside of the polygonal surface 2 of the rake face 8 in the cross section along the corner blade center line C 3 corner blade 3a corner blade 1st end 3b corner blade 2nd end 4 main cutting blade 4a main cutting blade 1st end 5 secondary cutting blade 5A 1st secondary cutting blade 5B 2nd secondary cutting blade 5a secondary cutting Blade 1st end 5b Secondary cutting blade 2nd end 6 Escape surface 7 Land part 8 Scoop surface part 8a Contact point with rear wall surface part 10 of rake face part 8 9 Top 9a Top 9 top 10 Rear wall surface 10a Corner blade center line Contact point between the rear wall surface 10 and the boss surface 2A in the cross section along C 11 Tool body 12 Insert mounting seat 13 Chip pocket 14 Clamp screw L Insert center line C Corner blade center line M Corner blade center line In the cross section along C An extension line from the apex 9a of the apex 9 to the inside of the polygonal surface 2 of the rake face 8 N A straight line connecting the corner blade 3 and the apex 9a of the apex 9 in the cross section along the corner blade center line C P reference surface Q boss surface 2A tangent line between A and rear wall surface portion θ1 Tilt angle of land portion 7 θ2 Tilt angle of rake face portion 8 H1 Corner blade center line C from corner blade 3 to apex 9a of top 9 in a cross section along the corner blade center line C Distance perpendicular to the corner blade center line C from the apex 9a of the top 9 to the intersection 2a in the cross section along the H2 corner blade center line C. Distance from the apex 9a of 9 to the contact point 10a in the direction perpendicular to the corner blade center line C A Parallel region B Inclined region G1 Arc radius formed by the corner blade 3 G2 Arc radius formed by the tangent line Q W1 Second secondary cutting edge 5B Width in the direction perpendicular to the insert center line L of the inclined region B in W2 Width in the direction perpendicular to the insert center line L in the parallel region A in the second secondary cutting edge 5B O Axis of the tool body 11 T Tool rotation direction

Claims

A mounting hole is opened on the front and back polygonal surfaces of the insert body formed in the shape of a polygonal plate so as to penetrate the insert body centering on the insert center line.
In a plan view from the direction of the insert center line, the edge portion of the polygonal surface has a convex arc shape centered on the corner blade center line parallel to the insert center line at the corner portion of the polygonal surface. Along with forming a corner blade, a main cutting blade extending linearly in the tangential direction of the corner blade is formed from the first end of the corner blade of the corner blade, and the first corner blade of the main cutting blade is formed. It is a cutting insert in which a secondary cutting edge is formed so as to recede from the first end of the main cutting edge on the side opposite to the end with respect to the extension line of the main cutting edge to the first end side of the main cutting edge. hand,
On the polygonal surface, a land portion that gradually protrudes in the direction of the insert center line is formed from the corner blade toward the inside of the polygonal surface, and on the inside of the polygonal surface than the land portion. , A rake face portion that gradually recedes in the direction of the insert center line is formed toward the inside of the polygonal face.
Within a range of 40 ° about the center line of the corner blade from the first end of the corner blade along the corner blade toward the second end of the corner blade opposite to the first end of the corner blade. In the cross section along the corner blade center line, the inclination angle θ1 of the land portion with respect to the reference plane perpendicular to the insert center line is equal to or greater than the inclination angle θ2 of the rake face portion with respect to the reference surface perpendicular to the insert center line. A cutting insert characterized by being present.
A convex curved top that is in contact with the land portion and the rake surface portion is formed between the land portion and the rake face portion in a cross section along the corner blade center line.
Inside the polygonal surface from the rake face portion, as the rake face portion extends toward the inside of the polygonal surface in a cross section along the corner blade center line toward the inside of the polygonal surface. A rear wall surface portion that gradually recedes in the direction of the insert center line, and a boss surface that is a plane perpendicular to the insert center line that extends from the rear wall surface portion to the inside of the polygonal surface to form an opening of the mounting hole. And are formed,
Within a range of 40 ° from the first end of the corner blade along the corner blade toward the second end of the corner blade about the center line of the corner blade, in the cross section along the center line of the corner blade. The distance H1 from the corner blade to the apex of the top in the direction of the insert center line in the direction perpendicular to the corner blade center line extends from the apex of the top to the inside of the polygonal surface of the rake face portion. The cutting insert according to claim 1, wherein the distance to the intersection of the line and the boss surface is H2 or less in a direction perpendicular to the corner blade center line.
Within a range of 40 ° from the first end of the corner blade along the corner blade toward the second end of the corner blade about the center line of the corner blade, in the cross section along the center line of the corner blade. The distance H3 in the direction perpendicular to the corner blade center line from the apex of the apex to the contact point or intersection of the rear wall surface and the boss surface, and the polygonal surface of the rake face portion from the apex of the apex. The ratio H3 / H2 to the distance H2 in the direction perpendicular to the corner blade center line to the intersection of the extension line inward and the boss surface is in the range of 0.45 to 0.70. The cutting insert according to claim 2.
Inside the polygonal surface from the rake face portion, as the rake face portion extends toward the inside of the polygonal surface in the cross section along the corner blade center line toward the inside of the polygonal surface. A rear wall surface portion that gradually recedes in the direction of the insert center line, and a boss surface that is a plane perpendicular to the insert center line that extends from the rear wall surface portion to the inside of the polygonal surface to form an opening of the mounting hole. And are formed, and within a range of 40 ° about the center line of the corner blade from the second end of the corner blade to the first end of the corner blade along the corner blade, the rear wall surface portion and the boss are formed. The tangent line or the intersection line with the surface is formed in an arc shape in the plan view.
In the plan view, the ratio G2 / G1 formed by the radius G2 of the arc formed by the tangent line or the line of intersection between the rear wall surface portion and the boss surface is 0.23 to 0.87 with respect to the radius G1 of the arc formed by the corner blade. The cutting insert according to any one of claims 1 to 3, which is within the range of.
The method according to any one of claims 1 to 4, wherein the corner blade is formed with a region extending along a direction parallel to the reference plane perpendicular to the insert center line. Cutting insert.
The polygonal surface is a rectangular surface formed 180 ° rotationally symmetric with respect to the insert center line, and is located at the corner portion where two corner portions located on one diagonal line of the rectangular surface are arranged. Claims 1 to 5, wherein the corner blade is formed, and the main cutting blade and the sub cutting blade are formed on the short side portion of the rectangular surface connected to the corner blade. The cutting insert described in any one of them.
The cutting insert according to claim 6, wherein the insert body has a front-back inverted symmetrical shape.
The cutting insert according to any one of claims 1 to 7 is formed on the insert mounting seat formed on the outer periphery of the tip end portion of the tool body which is rotated in the tool rotation direction around the axis. The corner blade formed in the corner portion of the one polygonal surface is directed toward the outer peripheral side of the tip of the tool body with the surface facing the tool rotation direction, and the first end portion of the corner blade of the corner blade. The main cutting edge extending from the tool body is directed toward the inner peripheral side of the tool body, and the clamp screw inserted into the mounting hole is screwed into the bottom surface of the insert mounting seat facing the tool rotation direction so that the tool body can be attached and detached. A cutting tool with a replaceable cutting edge, which is characterized by being attached.
A tool body for cutting tools with replaceable cutting edges.
The cutting insert according to any one of claims 1 to 7 is formed on the insert mounting seat formed on the outer periphery of the tip end portion of the tool body which is rotated in the tool rotation direction around the axis. The corner blade formed in the corner portion of the one polygonal surface is directed to the outer peripheral side of the tip of the tool body with the surface facing the tool rotation direction, and the first end portion of the corner blade of the corner blade. The main cutting edge extending from the tool body is directed toward the inner peripheral side of the tool body, and the clamp screw inserted into the mounting hole is screwed into the bottom surface of the insert mounting seat facing the tool rotation direction so as to be removable. A tool body that is configured to be mountable.